The chassis number sequences on the spiders are seemingly a bit erratic, presumably a product of the fact they were built at zagato and possibly not in sequence, records for other betas are not very good but at least the final chassis number for each month seems to always go up as you would expect!
I hope that one day someone will unearth the records for pre-78 it is a real shame that records are so sparse. It seems there are no records at all of individual cars, unless anyone out there knows any different?